Considerable evidence indicates olfactory, oral, gustatory, and visceral afferent information influences short term control of food intake. Recently we have demonstrated that gustatory, and possibly other oral afferents project not only to thalamus and neocortex, but also to ventral forebrain. The central distribution area of this ventral gustatory pathway also receives olfactory and visceral information. Lesion studies have implicated the area, called substantia innominata, in the control of feeding behavior. Part of this research will investigate the nature of the gustatory information reaching the area of substantia innominata, its interaction with other afferent information, and the role of this interaction in the control of feeding behavior. Sensory information influences ingestion, but the actual behavioral response to a particular stimulus depends significantly on the motivational condition of the organism. Gustatory stimuli reliably elicit ingestion or rejection responses which are subject to motivational manipulation. Utilizing gustatory stimuli and licking behavior simplifies the sensory-motor systems involved, while preserving the most basic components of feeding behavior. We have developed computer based techniques for recording electrophysiological responses from the gustatory relay nuclei to each individual lick in awake behaving rats. These procedures provide the necessary precision, yet are flexible enough to determine the significant gustatory information employed by the animal, and any alterations in that information resulting from motivational variables. Intestinal afferents synapse in the solitary nucleus as do gustatory afferents. Gustatory afferents have a bifurcated projection to forebrain, and evidence suggests visceral afferents may be similarly organized. Electrophysiological recording and experimental neuroanatomical techniques will be used to investigate the central projections of intestinal afferents in the vagus. Finally, two behavioral experiments are planned to determine the capacity of brainstem ingestion reflexes and the relative contribution of cortical and ventral forebrain to the control of tongue movements.